This invention relates to apparatus for feeding stacks of sheets, and more particularly to a flight conveyor apparatus for such purpose.
The invention is especially concerned with apparatus for feeding reams of paper, such as reams of 81/2" by 11" sheets of paper (a ream consisting of 500 sheets of the paper). Such reams are presently produced in vast quantities by means of an apparatus called a "sheeter", which cuts paper into sheets of the desired size (e.g., 81/2" by 11") and stacks up the sheets in reams of 500 sheets. The reams are then fed to a wrapper, wherein they are wrapped in a sheet of wrapping paper. In certain installations, the reams are fed into the wrapper by a flight conveyor apparatus, generally comprising a table having an upper surface on which the reams may slide, and endless conveyor means having flights spaced at intervals along its length for pushing the reams along the table, the endless conveyor means having an upper reach extending under the table in the direction of feed and movable in the direction of feed. Each flight has a section adapted in its travel with the upper reach of the conveyor to extend up through a longitudinal slot in the table, this section carrying a pusher plate adapted, as the flight moves forward with the upper reach of the coveyor, to travel over the table and push a ream forward on the table. Heretofore, it has been customary to provide the pusher plates with relatively narrow tabs extending down from their lower edge into grooves extending longitudinally of the table, to insure that the lower sheets of each ream are engaged and pushed forward. In many instances, however, it was found that these narrow tabs indented or gouged the lower sheet or a number of the lower sheets of the ream (at the trailing side of the ream in the course of its being pushed forward), such indentations being undesirable inasmuch as they tend to interfere with handling of the sheets in equipment, e.g., copying machines, in which the sheets are ultimately used. Consideration has been given to having the pusher plate extend down into a relatively wide groove (slightly wider than the plate) in the table to avoid the gouging effect of the narrow tabs, but this presented the problem that the reams tended to sag down into the groove with resultant undesirable marking of the ream along the edges of the table at the sides of the groove as the ream slides forward on these edges. Thus, there has been a problem of insuring that the lower sheet or sheets of a ream are pushed forward by the flights without damaging them.